<h1>Locked completion options</h1>

<p>
If at least one person has completed an activity, completion options are 
'locked'. This is because changing these options may result in 
unexpected behaviour.
</p>

<h2>Potential confusion</h2>

<p>
If somebody has ticked an activity as 
manually completed, and you then set it to automatic completion, the activity will 
become unticked - very confusing for the student who had already ticked it!
</p>

<p>
It is best not to unlock options unless you are sure it won't cause problems
- for example, if you know that students don't have access to the course yet,
so it will only be staff who have marked the activity completed when testing.
</p>

<h2>What happens when you unlock</h2>

<p>
Once you unlock options and then click
'Save changes', all completion information for the activity will be deleted and,
if possible, regenerated according to the new settings.
</p>

<ul>
<li>If the new completion option is manual, everyone will be set to 'not completed'
regardless of any previous setting.</li>
<li>If it is automatic then, depending on the options chosen, the system may or may
not be able to construct a correct current value for everyone.<ul>
<li>The 'viewed' requirement will not work - even if a student has viewed the
activity before, it will not be marked completed until they view it again.</li>
<li>Most other options will be recalculated successfully.</li>
</ul></li>
</ul> 

<p>
If you change completion options while a student is logged in, they may not see
the changes for some minutes.
</p> 

